Ralf Rangnick is at risk of repeating the same mistake as Ole Gunnar Solskjaer at Manchester United, which has already seen Cristiano Ronaldo put the futures of others in jeopardy.
Mason Greenwood and Marcus Rashford have emerged as the first victims of the five-time Ballon d'Or winner's exclusive treatment under the newly-appointed interim boss.
The academy graduates have growing concerns over game time at Old Trafford due to the Portuguese striker's untouchable status in the starting eleven. They have begun to explore their options, according to El Nacional and Mundo Deportivo.
Despite having warranted regular starts under their former boss, Greenwood and Rashford have struggled to nail first-team opportunities since Rangnick has taken the helm.
The England international's doubts can be stemmed back to United's signing of Ronaldo despite the club already being armed with an abundance of attacking options.
While the veteran has proved his weight in gold, Ronaldo's homecoming raised questions among some as to whether it was a football or business-led decision.
Both have reaped incredible rewards. However, United are beginning to see the consequences of signing a world-class forward without considering the viability.
Ronaldo was an excellent signing, but the principle of adding another attacker wasn't; United now face a situation where they must lure Greenwood and Rashford back into the fold.
But, Rangnick is at risk of repeating the same narrative following the Red Devils' interest in Porto's Luis Diaz.
United have joined Man City, Liverpool and Newcastle in the race to sign the winger's signature at the end of the season, according to Calciomercato.
The 24-year-old, who's got an €80 million (£68m) price tag according to Portuguese news outlet SAPO Desporto, has been in impressive form this season with 13 goals and three assists in all competitions.
Despite his impressive displays, United must learn from their mistakes and ensure that Rangnick isn't overstocked with options.
However, should the Red Devils win the race for Diaz, then the Colombian international will be reunited with former Porto teammates Alex Telles which naturally puts Luke Shaw's future at threat.
Diaz and Telles have occupied the left-wing together 44 times, winning the Portuguese domestic double in 2019/20, and their pre-conceived chemistry could well and truly spell the end of Shaw's time as a starter.
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